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Exobiologyon Mars

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Report of the workshop "Exobiology Instrument

Concepts for a Soviet Mars 94/96 Mission"held at NASA Ames Research Center

Moffett Field, California

February 27-28, 1989

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NASA Conference Publication 10055

Exobiologyon Mars

Edited by

D. L. DeVincenzi, J. R. Marshall, and D. AndersenNASA Ames Research Center

Moffett Field, California

Report of the workshop "Exobiology Instrument

Concepts for a Soviet Mars 94/96 Mission"held at NASA Ames Research Center

Moffett Field, CaliforniaFebruary 27-28, 1989

National Aeronautics and

Space Administration

Ames Research Center

Moffett Field, California 94035-10001990

PREFACE

Mars has long fascinated exobiologists. Of all the planets in the solar system aside from Earth,

Mars holds the most promise for unlocking the secrets of the origin and evolution of life. Indeed,

Mars may contain ancient clues to the origin of life that are unavailable on the more dynamic Earth.

In legend, Mars has long been associated with life; someday, the planet may reveal whether that

association has a foundation in reality.

Programs of Mars exploration were begun by the United States and the Soviet Union during the

1960s, and continued in the 1970s. The missions conducted by the United States anchored the foun-

dations of Mars planetology and culminated for exobiologists in the Viking search for life on the sur-

face of Mars. Although this extraordinary pursuit added much to our knowledge of the planet, the

Viking lander experiments seemed to rule out organic life on the surface. However, the orbiter

images from both Viking and Mariner offered a glimpse of an earlier Mars that may have been more

hospitable to life as we know it.

We may again be embarking on a course that will lead to more extensive exobiological investi-

gations of Mars. The Soviet Union's Phobos missions initiated an extensive program of Mars explo-ration that includes an additional mission or set of missions in 1994 and 1996 and culminates in a

Mars Rover and Sample Return mission as early as 1998. The United States has also scheduled a

Mars launch with the Mars Observer in 1992, and a Mars Rover and Sample Return mission is under

extensive study for a potential launch by the turn of the century. Human missions to Mars are also

under study in the United States, with the exobiological study of Mars a prime science goal.

Perhaps the most encouraging note in this renewed emphasis on Mars is the unfolding interna-

tional cooperation. U.S., Soviet, and European scientists are cooperating on mission studies, landing-

site selection, and, of course, planning for exobiology studies of Mars. This workshop report presents

investigations that may be proposed for missions within both the U.S. and Soviet programs. As such,

it will help mission planners in all participating nations understand the nature of the instrumentation

associated with exobiological investigations to be conducted on Mars.

John D. Rummel, Ph.D.

Program Manager,

Exobiology

NASA Headquarters

Washington, DC

August 1989

o.o

111

¢l_J._.,..._'t_l_ _,i,_ PRBCEDING PAGE BLANK NOT FILMED

TABLE OF CONTENTS

Page

PREFACE ......................................................................................................................................... iii

ABSTRACT ..................................................................................................................................... vii

INTRODUCTION ............................................................................................................................. 1

INSTRUMENT CONCEPTS ............................................................................................................. 3

THE USE OF NEUTRON SCATTERING FOR THE DETECTION OF

WATER AND ORGANICS ON THE SURFACE OF MARS .............................................. 3

B. Clark, W. Gardner, and A. Seiff

SPECIFIC-ELECTRODE MEASUREMENT OF CHEMICAL PROPERTIES

OF THE MARTIAN SOIL .................................................................................................... 5

B. Clark, S. Chang, and J. Oro

SURVEY OF OXIDANTS IN THE MARS NEAR-SURFACE LAYER ............................ :.... 9

C. Stoker, A. Seiff, H. P. Klein, C. McKay, and R. Day

THE ANALYSIS OF MARTIAN SOIL VOLATILES USING A THERMAL

PROCESSOR/EVOLVED GAS ANALYZER ................................................................... 15

G. CarIe, R. MancinelIi, and R. Wharton

THE DETECTION OF ORGANICS AND VOLATILES WITH MASS

SPECTROMETRY .............................................................................................................. 17

A. Nier, J. Oro, D. Des Marais, and D. Rushneck

BIOLOGICAL PATTERN RECOGNITION IN MARS IMAGING ........................................ 23

E. L Friedmann and D. Schwartz-Kolyer

INFRARED LASER SPECTROMETER FOR IN SITU SENSING OF

THE MARTIAN ATMOSPHERE ....................................................................................... 25

C. Webster, T. Owen, and D. Hunten

THE DETECTION OF ANAEROBIC CHEMOAUTOTROPHS ON MARS ......................... 27

C. McKay

SUMMARY AND RECOMMENDATIONS .................................................................................. 29

WORKSHOP PARTICIPANTS ...................................................................................................... 31

ADDITIONAL CONTRIBUTORS ................................................................................................. 32

V

PRECEDING PAGE BLANK NOT FILMED

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

LIST OF FIGURES

Page

Neutron spectrometer ....................................................................................................... 5

Chemical properties of Martian soil ................................................................................. 9

Soil-oxidant survey instrument ...................................................................................... 13

In situ alternative to oxidant survey instrument ............................................................. 14

Schematic of differential thermal analyzer/gas chromatograph (DTA/GC) .................. 17

Mass spectrometer using Mattauch Herzog geometry ................................................... 21

Schematic of complete mass spectrometer analytical system ........................................ 21

vi

ABSTRACT

This report contains descriptions of several instrument concepts that were generated during a

workshop titled "Exobiology Instrument Concepts for a Soviet Mars 94/96 Mission" held at NASA

Ames Research Center on February 27-28, 1989. The objective of the workshop was to define and

describe instrument concepts for exobiology and related science that would be compatible with the

mission types under discussion for the 1994 and 1996 Soviet Mars missions. Experiments that use

existing technology were emphasized. The concepts discussed could also be used on U.S. missionsthat follow Mars Observer.

vii

INTRODUCTION

The workshop "Exobiology Instrument Concepts for a Soviet Mars 94/96 Mission" was held at

the National Aeronautics and Space Administration (NASA) Ames Research Center, Moffett Field,

California, on February 27-28, 1989. It was conducted at the request of Dr. Geoffrey A. Briggs,

Director, Solar System Exploration Division, and Dr. John D. Rummel, Program Manager,

Exobiology, Life Sciences Division.

The objective of the workshop was to define and describe instrument concepts for exobiology

and related science that would be compatible with the mission types under discussion for the 1994

and 1996 Soviet Mars missions. Experiments were emphasized that use existing technology, primar-

ily Viking or Viking derived. The concepts discussed could also be used on U.S. missions thatfollow Mars Observer.

While final decisions have not been made about the spacecraft to be used for the Soviet 94/96

opportunity, some potential specifications have been given. Included are the following: orbiters with

approximate science payloads of 200 kg and data links of 64 kbytes/sec; balloons with 10- to 15-day

lifetimes and approximate science payloads of 5 to 6 kg divided between the gondolas and the

draglines (or "snake tails"), which would come into contact with the Martian surface during the

cooler hours of darkness; penetrators that could last 2 to 3 days (or up to 6 months if radionuclide

power sources are used) and that would have science payloads of approximately 2 to 3 kg; small

instrument packages or "eggs" that would be deposited onto the Martian surface and that are largely

undefined but are expected to have maximum payloads of 3 kg; and landers and rovers that could

provide larger instrument platforms.

Participants in this workshop evaluated the scientific opportunities offered by the potential mis-

sion vehicles in light of post-Viking knowledge about Mars. They then developed specific instru-

ment concepts tailored to specific vehicles. These concepts were discussed at the workshop, and par-

ticipants provided suggestions for implementation. The product of the workshop, a set of potential

exobiology experiments for the Soviet Mars 94/96 opportunity, is described herein.

Following the workshop, two additional experimental concepts were identified; they are also

included in this report. The first of these describes the use of an infrared laser spectrometer for in situ

measurements of the Martian atmosphere, and the second describes a method for life detection. Both

concepts address questions important to exobiological science objectives on Mars, and both are

compatible with the mission probes highlighted in the workshop.

As indicated in "Summary and Recommendations," exobiology science objectives for Mars

exploration were not extensively discussed at the workshop and, therefore, are not described in detail

in this report. Participants were assumed to be familiar with the importance of developing experi-

ment concepts that would shed light on questions of chemical evolution and extant or extinct life on

Mars. If more detailed information on the rationale and strategy for exobiological investigation of

Mars is desired, the reader is referred to other documents (e.g., C.P. McKay and C.R. Stoker, The

Early Environment and its Evolution on Mars: Implications for Life, Reviews of Geophysics, 27 (2),

189-214, 1989).

A comprehensive description of all important exobiological experiments for all classes of Mars

spacecraft was well beyond the scope of this workshop. This workshop was restricted to the consid-

eration of experimental concepts that would be compatible with the spacecraft of limited weight,

power, and volume that are being considered by the U.S.S.R. for the 94/96 opportunity (and by the

U.S. for, for example, the Mars Environmental Survey mission). Participants also limited their con-

siderations to concepts that did not require extensive research and development, and whose technol-

ogy had been previously described and/or was readily available. Finally, the timing of the workshop

was such that extensive development of ideas either before or after the workshop was not possible.

This report, therefore, is the product of a rather limited activity. The spontaneity of the discussions

and the preliminary nature of some of the concepts are reflected in the somewhat uneven and brief

descriptions included here. More complete and rigorous treatment of the concepts would require a

significantly expanded design effort.

2

INSTRUMENT CONCEPTS

THE USE OF NEUTRON SCATTERING FOR THE DETECTION OF WATER AND

ORGANICS ON THE SURFACE OF MARS

B. Clark, W. Gardner, and A. Seiff

Objectives

The objective of this experiment is to detect water and organic molecules on or just beneath the

surface of Mars. Knowledge of the amount and distribution of water on Mars is of critical impor-

tance to an assessment of many physical and chemical processes that may have been operative at

some time in the history of the planet. Additionally, the presence of organic molecules might provide

evidence for past or present Martian biota. A neutron-scattering experiment would survey the hydro-

gen content of the Mars soil, with the range of detection being dependent on the depth of deployment

of the detector. A significant signal would indicate the presence and amount of hydrogen, which is

most likely associated with water (probably as subsurface ice), but is possibly associated with

organic molecules because typical organic compounds are 20 to 50% hydrogen atoms. It is expected

that the inventory of water will greatly exceed that of any organic molecules. This measurement,

combined with an independent water-detection experiment, could place an upper limit on the quan-

tity of organics in the soil. It is expected that the device would also detect chemically bound hydro-

gen in clays and other minerals, but independent analyses of the soil composition would allow that

signal to be subtracted.

Proposed Instruments

The instrument proposed for this experiment is a neutron spectrometer. The basic unit would

consist of a source of fast neutrons (a radioactive pellet) placed in fixed geometry with respect to a

slow-neutron detector. Because hydrogen has a large scattering cross section for neutrons, the flux of

thermalized (slow) neutrons returned to the detector would reflect the abundance of hydrogen atoms

in the soil.

Experimental Protocol

Upon activation, the detector would measure hydrogen concentrations within a range of 1 m

from the instrument's deployment position. The required counting time would be short, on the order

of minutes. Once deployed, a fixed probe could possibly monitor changes, if any, in hydrogen con-

centration in the regolith over time. If a long-lived power supply were provided, measurements could

be obtained during all Martian seasons, and observed changes in the amounts of water present would

clarify the possibility of a Martian hydrological cycle.

3

Mission Compatibility

The neutron spectrometer could be mounted in a penetrator or a balloon snake tail, as shown in

figure 1, in an egg, or on a rover. If mounted on a snake tail or a rover, the instrument could measure

the geographic variability of hydrogen and identify the regions of greatest biological interest, i.e.,

regions high in water and/or organic molecules.

The length of the counting times requires that the instrument be at rest during a measurement

cycle. This poses no difficulty for penetrator or egg applications. If the instrument were mounted on

a rover, the measurement cycle could perhaps be coordinated with the expected pauses in the rover's

movement. For the snake tail, measurements either would require a period of low nocturnal wind, or

the results would be average measurements over terrain covered during the cycle.

Evaluation of Current Technology

Instrument weight, power, and data requirements can only be estimated prior to design studies,

but the neutron spectrometer probably could be built to weigh less than a few kilograms, with corre-

spondingly modest power and data-rate requirements. The neutron source, detector, and associated

electronics could be miniaturized for use on low-payload carders to be deployed on the Martian

surface.

Telemetry of data appears straightforward and no major problems are foreseen with this well-

established technology. Development time should be compatible with a 1994 or 1996 mission.

4

Neutron source Detector

Molecules ....containing ..... _H atoms

.....................

Snake tail application

..............

Penetrator application

Figure 1. Neutron spectrometer.

5

SPECIFIC-ELECTRODE MEASUREMENT OF CHEMICAL PROPERTIES OF THE

MARTIAN SOIL

B. Clark, S. Chang, and J. Oro

Objectives

The objective of this experiment is to measure a number of important chemical properties of the

Martian soil, such as Eh, pH, cations, anions, and oxidant content. These properties would be mea-

sured under aqueous conditions in order to determine the abundances and states of the biogenic ele-

ments (C, H, N, O, P, S) in the soil, the influence of past aqueous regimes on the weathering of

rocks, and the transport of H20 and other volatiles from depth at any given site. The experiment

would also provide insight into chemical hazards to the spacecraft posed by fine-grained, wind-

blown dust; potential toxicity, to the crew, of the Martian soil; and in situ resource utilization by

humans. Preparations for future human missions to Mars must consider these and other environmen-tal constraints.


The basic instrument package (fig. 2) would consist of a wet-soil processor capable of chemical

electrode measurements of Eh; pH; anions such as CI-, CO3--, HCO3-, NO2-, NO3-, SO4--,

PO4---; and cations such as Ca ++, Mg ++, Na +, K ÷, Al++, Fe ++, Fe +++. A particle light-scattering and

settling cell for size-distribution measurements would also be included. The actual number of spe-

cific electrodes employed on a mission would depend on mission constraints and choices (as yet

unmade) regarding the most important of these measurements.

If the instrument were interfaced with a calorimeter/spectrometer, measurements of anions and

cations not detectable with electrodes would be possible. To determine cation and anion abundances

and identities, the Eh and pH electrodes could be combined with an ion-chromatograph.

If the basic package were joined with an evolved gas analyzer (EGA) (mass spectrometer or gas

chromatograph), species such as CO2, NxOy, SO2, oxidant-O2, and other volatiles liberated by H20and acids could be measured.

Soil-mass measurements could be made by radiation attenuation, volume, or microbalance.

Added thermocouples could be used for measurements of the heat of hydration. Elemental analysis

of leachates or evaporated residues could be made by the addition of an x-ray fluorescence (XRF)

spectrometer.

The basic unit would weigh approximately 2 kg. With the augmentations discussed above, the

weight would be approximately 6 kg and the volume would be 500 to 1500 cc, including electronics.

Power consumption would be approximately 2 to 4 W (basic unit + EGA or XRF spectrometer), and

data output would be 100 bits/sec.

__ttBONA&&tf Bj._t_PRECEDING PAGE BLANK NOT FILMED


The number of experiments to be conducted would depend on available payload mass and vol-

utne and on the variability of the soil at various ranges of sample sizes. This number could be any-

thing from 3 to 21; the latter may be close to the operational limits of the spacecraft (e.g., time or

data-transmission constraints). The time required for each experiment would be approximately 3 to

12 hr. Each experiment would require 0.1 to 0.5 cc of sieved soil. After the sample mass is deter-

mined, H20 (or some other suitable liquid) would be added to the soil, and any gases released at that

time would be analyzed by the EGA. The electrode properties of the H20/soil mixture would then be

measured as a function of some predetermined period of time. The leachate would be drained into

another vessel, and a similar measure of electrode properties as a function of time would be made of

the leachate, in order to determine the composition of soluble ions. The soil sample could then be

analyzed by XRF spectroscopy. After the final analysis, the soil sample and leachate would be

discharged so that the experiment may be repeated as necessary. Measurements of chemical

abundances and properties of the samples would be based on signal intensities. Definitive

interpretations would be based on calibration curves for the electrodes.


The experiment and the instruments used could be scaled to suit a range of mission types, from

eggs and penetrators to rovers. If flown as part of a penetrator mission, this experiment could be used

to characterize possible landing sites for robotic sample-return missions or human exploration.


The wet chemical analysis, XRF spectrometer, and soil-handling capabilities have a strong

inheritance from Viking; the EGA, from Viking and Pioneer Venus; and the valves, from the devel-

opment of Comet Rendezvous/Asteroid Flyby (CRAF) hardware. This instrument package would

require gas and liquid valves, mass-measuring devices, liquid reservoirs, a sample-acquisition

device, liquid dump lines, solid-waste storage or disposal systems, soil sieves (< 1 mm), liquid feed

and purge lines, and possibly a drill sampler if on a penetrator. Minimal technology development

would be required, although flight qualification of the existing technology is necessary. Develop-

ment of electrodes that have the ability to survive high-G loads or to maintain stability over long

mission lifetimes would be required.

To EGA (GC or MS)

IIGas outlet

Sensing electronics(Eh, pH)

Seal

Liquid injection

Soil extraction chamber sample

Celorlmetrlcsensor

Liquid analysis cellQ

XRF

Liquid outlet

Waste liquid

Sensing electrodes

(Ion specific)

Figure 2. Chemical properties of Martian soil.

9

SURVEY OF OXIDANTS IN THE MARS NEAR-SURFACE LAYER

C. Stoker, A. Seiff, H. P. Klein, C. McKay, and R. Day

Objectives

One of the most important aspects of this experiment is its relevance to the question of extant

life on Mars. The proposed explanation of the Viking Biology Instrument results, particularly the

Labeled Release (LR) and Gas Exchange (GEx) experiments, was that they reflected a suite of oxi-

dants in the Martian soil that may have degraded the organics that were added in the experiments.

However, the results of the LR experiment were also consistent with biological activity. In the pro-

posed experimental concept, the LR experiment would be reconfigured to distinguish between

organic degradation produced by oxidants and that produced by biological activity. The experiment

could yield valuable information, whether or not oxidants are found. If the oxidants hypothesized to

explain the LR activity were not found, then the case for biological activity would be strengthened. If

the distribution of oxidants could be described, it would be possible to determine locations and

depths that would avoid oxidants and then to search for evidence of extinct life and/or chemical evo-

lution. Also, future experiments could be designed to detect certain "intractable" organics (e.g., kero-

gen) that may be more resistant to degradation.

This experiment could shed light on two major questions raised by the Viking results: 1) Are

indigenous organic molecules absent because of their destruction by oxidants? 2) What is the spe-

cific nature of the oxidants, and how are they distributed over the planet? It is important to under-

stand if they are everywhere, or if there are specific locations (e.g., polar regions or subsurface) that

are free of oxidants. In the absence of direct mineralogical information about oxidants, this experi-

ment emphasizes the effect rather than the composition of the oxidants.


Detectors specific for 14C and 02 would be used to avoid the complexity and size requirements

of a gas chromatograph or mass spectrometer. The instrument would incorporate mechanisms for

humidifying or wetting the soil with an aqueous solution, and if sufficient power were available, the

instrument would provide heaters to permit comparative measurements of heated and unheated soil

samples. This would assist in elucidating the nature of the oxidants. If the instrument had controlled

thermal ramping, it would be possible to obtain information on potential peroxides and superoxides

by measuring the 02 evolved versus temperature. Where feasible, the instrument could be combined

with a differential thermal analyzer/evolved gas analyzer (DTA/EGA). The estimated volume of the

instrument is approximately 0.5 liter. A reasonable estimate for the weight of the identified

components is ~ 1 kg. Diagrams of the soil-oxidant survey instrument can be seen in figures 3 and 4.

11

_Alll_.lO .t_'IINT_ _,_ PRECEDING PAGE BLANK NOT FIL,___'D


The soil could be humidified and then wetted once per sample. The primary measurement would

last several hours, but extended release of 02 could be monitored for several days, if desired. The

soil sample size would be approximately 0.5 cc.

A soil sample would be taken into a chamber for analysis at each location in the survey. The

analysis may include the following steps: A sample would be heated gradually, while evolved oxy-

gen is detected. The rate of oxygen released as a function of sample temperature would be character-

istic of the oxidants present and could be compared with laboratory results to identify the oxidants. A

second sample would be humidified while oxygen release is monitored. Oxygen release in the pres-

ence of water is a characteristic of candidate oxidants (e.g., superoxide) identified by the Viking

experiments. This procedure, used in the Viking GEx Experiment (in which the humidifying agent

included nutrients), would verify Viking observations. It would be conducted at multiple locations to

determine the variability of oxidant concentrations in the soil. To determine the amount of molecular

oxygen that may be adsorbed and stored in interstitial spaces in the Martian soil, an inert fluid would

be added to a sample while oxygen release is monitored. Other reagents would be added to the

sample. Candidate reagents include well-characterized organics labeled with 14C, which would be

released in gaseous form (as is known from the results of the Viking LR Experiment). Gas (presum-

ably CO2) containing 14C would be measured by a 14C detector. This would reveal the effectiveness

of the oxidants in the soil in destroying organic molecules; the time course of the gas released could

be used to assay the nature of the process and the quantity of oxidants.

The experiment must be able to examine multiple soil samples at each location. A possible

method for doing this, by inserting an open-ended sampling tube into the soil, is shown in figure 4.

The sampling tube would include an electrical heater in the tube wall. This may present some prob-

lems regarding uniform heating of the soil, but this would be one of the first questions to be

addressed during design studies in pre-phase A activities.


The objectives of this experiment could probably be achieved in a sequence of missions, starting

with the simplest experiments on the early, low-weight-capacity missions and continuing with more

complex experiments carded on subsequent missions with larger payloads. In its simplest form, an

instrument of this type would be compatible with balloon snake tails, eggs, and penetrators. More

sophisticated instruments using the same basic concepts, perhaps with more reagents and more elab-

orate thermal analysis, could also be deployed on rovers, which would also offer the opportunity to

study the geographical distribution of oxidants.


Existing Viking technology could be used for the pressurization gas supply, isolation valve,

solution reservoir, solenoid valve, flow restrictor, and 14C detector (see fig. 3). The pressurization

12

gas supply is a small, unregulated volume (not a carrier gas supply). The O2-specific detector would

be a new technology, but several approaches are available. The major technology issue would be the

collection (and dumping) of soil samples in a balloon snake or an egg. In the case of the snake, the

soil could be collected either by scraping or by the tube-injection system described above.

Pressurization gas

Isolation valve

_--- Solution purge vent

Z_ Latching valves

14C organics inwater reservoir

Flowrestrictor

Vent

14C detector

0 2 specificdetector

Soil

Figure 3. Soil-oxidant survey instrument.

13

0 2 detector

Surface soil

H 2° and reagent injection

14C

element

detector

Figure 4. In situ alternative to oxidant survey instrument.

14

THE ANALYSIS OF MARTIAN SO_ VOLATILES USING A THERMAL

PROCESSOR/EVOLVED GAS ANALYZER

G. Carle, R. Mancinelli, and R. Wharton

Objectives

The objective of this experiment is to obtain an inventory of the volatiles in the Martian soil.

Materials to be searched for include permanent gases, organics, and some evaporites (carbonates,

sulfates, nitrates, nitrites, etc.). It is proposed that loose surface materials (soils, aeolian dust, small

rocks, and ices) or consolidated materials in sediments and rock outcrops be subjected to thermal

analysis.

Coupling a differential thermal analyzer (DTA) with a gas chromatograph (GC) would enable the

detection of the physical changes associated with the volatilization of substances; this could provide

important mineralogical information. In addition, the instrument would allow the determination of

the temperature and possible enthalpy of mineral decomposition reactions in Martian soil, along with

the measurement of the amounts of associated evolved gases, as aids in identifying the minerals pre-

sent. The combination of thermal and effluent gas analysis would help distinguish between phase

changes involving water from those involving CO2 and other volatiles. From the amounts of water

vapor evolved from minerals (determined by a GC) and the temperature and heat capacity at which

gas evolution occurred (determined by a DTA), soils could be qualitatively characterized as to their

clay content and the presence or absence of hydrated minerals that decompose at different

temperatures.

Data obtained by the proposed instrument would provide answers to many questions currently

surrounding the inventories and chemistry of H20, CO2, CO3--, N2, NOx, H2S, SO4--, organic

material, and other volatile compounds that may be present on the surface of Mars. The elemental

composition of the Martian surface regolith was determined by the Viking landers using x-ray fluo-

rescence and may be a mixture of iron-rich smectite clays (e.g., montmorillonite, scapolite, nontron-

ite), but this is unclear. By analyzing the surface material with an autonomously operating DTA/GC,

this identification could be clarified.


Heating of materials, either stepwise or continuously, would occur in a hermetically sealed,

heated chamber containing a known volume or weight of Martian surface material. This would be

coupled with the monitoring of evolved gases and thermal events (both endothermic and exother-

mic). A schematic of such a DTA/GC system can be seen in figure 5.

For the proposed thermal analyzers, a range of complexity is available, from simple pyrolysis to

differential scanning calorimetry. For near-term Soviet missions, simple pyrolysis may be the most

practical. Simple pyrolysis involves the stepwise heating of a sample followed by analysis with an

15

evolvedgasanalyzer(EGA).Simplepyrolysiswouldnotprovidedetailedinformationaboutthermaleventssuchasphasechangesin thesamplebeinginvestigated;however,it wouldoffer a lessexpen-sive,smaller(volumeandmasscanbe5to 10%lessthanaDTA or DSC),morerobustinstrumentdesign.For future,lessconstrainedmissions,adifferentialthermalanalyzer(DTA) or a differentialscanningcalorimeter(DSC)wouldbepreferred.

Theconfigurationof theproposedEGA couldrangefrom single-compoundmoleculardetectors(e.g.,CO2electrodes)to complexgaschromatographsand/ormassspectrometers.

Specificationsof a simpleDTA/EGA (for penetratorapplication)are:volume,-2 liters;mass,-2.5 kg; andpower,-20 W-hr peranalysis.

In additionto theabove,this instrumentwould requirespacecraftsupport(for datahandlingandtransmission)aswell asasystemto obtainsamplesandtransferthemto theinstrument.


Heating samples in a stepwise fashion would volatilize adsorbed water and gases (e.g., CO2 and

lower molecular weight organic compounds) first. At progressively higher temperatures, water from

mineral dehydration, CO2 from decomposition of bicarbonates, and volatiles from pyrolysis of

higher molecular weight organics would be released. At the highest temperatures, NOx would be

released, as well as additional water and CO2 from more stable species.

For near-term Soviet missions, the best instrument would be a simple, stepwise thermal-

processing chamber that heats material to approximately 700 °C and identifies the gases evolved

with a two-column Viking-type gas chromatograph. A sensitive helium-ionization detector, capable

of detecting compounds to the picogram level, could be employed to provide a thousandfold increase

in sensitivity (this type of detector has been successfully flown on Soviet Venera missions).

Operation of the proposed DTA/EGA would begin with the collection of the sample to be pro-

cessed by the thermal analyzer. The DTA would begin a standard analysis by heating the reference

standard and the sample. When an event such as a phase change occurs, the differential signal would

be used to trigger operation of the EGA, which would collect and analyze a sample of gas from the

chamber. Use of a highly sensitive pressure transducer able to detect the presence of evolved gas

may also be a method of triggering operation of the EGA. Also, gas sampling could be conducted at

preset time intervals.


The instrument could be flown on any lander spacecraft (eggs, penetrators, rovers, surface lan-

ders) that can accommodate surface-material sampling with a minimum of approximately 20 W-hr of

power per analysis. Simple pyrolysis in conjunction with an EGA may be practical for use in eggs or

penetrators if sample acquisition and delivery systems are developed. Although there have been

design studies for the placement of a DSC/EGA into the body of a comet penetrator, this may prove

16

toodifficult to adaptfor near-termmissionsto Mars.A DTA/EGA or a DSC/EGAcouldbeplacedonalargerplatformsuchasaMartianrover.


The instrument concept for the DTA/EGA is based on extensive experience with GC/mass spec-

trometer (MS) flight experiments and development activities, acquired over the past two decades

with projects such as Viking, Pioneer Venus, and Comet Rendezvous/Asteroid Flyby (CRAF). Her-

itage for the proposed DTA is based on Viking instruments such as the Viking Biology Processor

and the GC/MS. The automation of the DTA/EGA system prior to its use on the Martian surface

would require additional technology development.

Column

Column

DTA GC

Detectorsystem

Gasinlet

Figure 5. Schematic of differential thermal analyzer/gas chromatograph (DTA/GC).

17

THE DETECTION OF ORGANICS AND VOLATILES WITH MASS SPECTROMETRY

A. Nier, J. Oro, D. Des Marais, and D. Rushneck

Objectives

Low-mass-range (2 to 150 amu) mass spectrometry would be an excellent method for the analy-

sis and identification of volatile organic and inorganic compounds on the surface or subsurface of

Mars. With present technology, a miniature mass spectrometer, about one-half the size of the Viking

gas chromatograph/mass spectrometer (GC/MS), would be capable of analyzing organic molecules

and other volatile compounds of the biogenic elements (C, H, N, O, P, S).

Information about chemical composition could help determine whether prebiotic chemistry and

biological evolution occurred on Mars. If a near-subsurface sample rich in organic matter can be

obtained from ancient Martian sediments, and if the molecules in the sample are sufficiently diverse,

it may be possible to determine whether the organic molecules were synthesized by abiotic chemical

processes or were the result of later biological activity.

If the mass spectrometer were coupled to an appropriate inlet system, this method would also

allow the measurement of water vapor, CO2, SO2, NO2, and other volatile forms of the biogenic

elements, as well as the determination of their isotopic composition. This in turn would provide

information about the mineralogical composition of the Martian surface and of subsurface materials

that may be retrieved by drilling or other methods.

The knowledge that may be obtained by this instrument would not only be interesting in terms of

understanding past Martian chemical or biological evolutionary processes, but would also enhance

understanding of past atmospheric conditions and the occurrence of sedimentation (involving liquid

water) and evaporation.

The record of gas compositions and sample-heating behavior would be related to the decomposi-

tion of minerals, adsorbed gases, and entrapped organic materials in the samples. Interpretation of

this record would likely provide definitive testimony regarding the presence and nature of carbonate

and nitrate minerals as well as reduced sulfur, nitrogen, and carbon (organic) compounds. In addi-

tion, the stable isotopic compositions of hydrogen, oxygen, carbon, nitrogen, sulfur, etc. could be

measured in the evolved gases, perhaps to a precision of a few tenths of a percent. These isotopic

measurements could be related to the mineralogical phase changes that released gases during the

analysis, providing insights into the origin and history of the phase changes.


Magnetic-deflection and quadrupole mass spectrometers have been used in space-related studies.

Weight, volume, and power consumption are roughly the same for the two types of instruments. In

general, the magnetic types are more stable and provide higher precision; they are recommended for

19

PRECEDING PAGE BLANK NOT FILMED

the proposed missions. Double-focusing (angle and velocity) magnetic instruments provide higher

performance and wider mass range than the single-focusing (angle only) type for the same weight

and volume, and have been employed on numerous terrestrial rocket flights; the Atmosphere

Explorer C, D, and E satellites; the Viking spacecraft; and the "bus" of the Pioneer Venus mission.

A schematic of the instrument (using the Mattauch Herzog geometry) is shown in figures 6 and 7.

A flight mass spectrometer capable of covering the mass range of 2 to 150 amu, including pumps

and electronics but not data-storage, would have a volume of approximately 0.02 m 3, a weight of the

order of 6 kg, and a power consumption of 8 W. Standby power would be only a fraction of a watt.


This instrument would be carried on a rover to multiple sampling sites and, based on estimated

spacecraft resources, would perform between 6 and 12 analyses total. Each experiment might require

2 to 4 hr; most of this time would be used for careful, controlled heating of the sample to 700 °C.

Sample sizes might range from 500 I.tg to 5 mg.

In a typical experiment, a sample prepared by crushing and sieving would be introduced into the

heating chamber and deposited on the heating stage. The heating chamber would be sealed and evac-

uated using the attached vacuum pump. During evacuation, the chamber atmosphere, which would

include Mars atmosphere plus any gases evolved from the sample, would be analyzed by the mass

spectrometer. The pressure of the gas stream to be analyzed would be reduced by a pumping system

similar to one already developed for analyses of Earth's upper atmosphere. The sample would then

be heated by a differential thermal analyzer (DTA) at a rate sufficiently slow to detect events caused

by phase changes and chemical reactions. Any gaseous products of these events would be monitored

continuously by the mass spectrometer. The heating and analysis would continue until a temperature

of perhaps 600 to 700 °C is attained. At 700 °C, any carbonates present would have decomposed

under vacuum. The data would include a record of sample temperature and heating energy as a

function of time, synchronized with a continuous time record of mass spectrometric analyses (2 to

150 amu) of the evolved gases.


The weight and power requirements of mass spectrometers are likely to exceed the capabilities of

eggs, penetrators, or balloons. Therefore, landers or rovers would provide the best surface platforms

from which to operate these instruments.


Together with the abundant information that could be obtained by heating samples, the chief

value of this instrument would be its great sensitivity and broad applicability to the identification and

isotopic measurements of gases evolved from a heated sample. The instrument has a heritage from

previously constructed mass spectrometers, ovens, sample-handling systems, etc., on Viking and

20

Pioneer Venus. No major new technology would be required for the construction of a flight-qualified

mass spectrometer, and no other instrument would match the mass spectrometer's ability to identify

gases unequivocally and measure their isotopic composition.

GasInlet

,ectronmu,t,p,,ers--P_/_

[!_/_/M Magnetic' w _ //H analyzer

Retractable _ +J/A;[i'._ .. Electric _.-.--_g///H Trap

fla" _analyzer_[I_ _ /chamber

I' iL__ / [source1_1 I,I I,I I,/

Pump I Pump 2 Pump 3 Pump 4

Figure 6. Mass spectrometer using Mattauch Herzog geometry.

SampleInput

Pump

Oven-MSinterface

I 1III

__1_ Soil

Oven for controlledheating& DTA

Pumps

-- Heatingstage, which includesDTA

Mass spectrometer

Figure 7. Schematic of complete mass spectrometer analytical system.

21

BIOLOGICAL PATTERN RECOGNITION IN MARS IMAGING

E. I. Friedmann and D. Schwartz-Kolyer

Objectives

The objective of this experiment is to detect evidence of a Martian biota, extinct or extant. The

experiment concept is based on the observation that endolithic microorganisms on Earth (in desert

ecosystems in Antarctica and other areas) produce variegated (mosaic) patterns on rock surfaces that

are distinguishable from nonbiogenic patterns. An extended area of the Martian surface could be sur-

veyed using the imaging systems on surface-deployed vehicles to identify possible sites of fossil (or

extant) life. Select, high-resolution images returned to Earth could then be analyzed, using a neural-

network or artificial-intelligence computer program to recognize patterns in rock surface structures

produced by endolithic biological activity. The program would be modified in the course of its

development to enable it to discriminate between biogenic and abiotic patterns.


This experiment would use imaging systems, placed on the surface of Mars, that are capable of

resolving objects approximately 1 cm in size. The maximum number of such high-resolution images

should be taken and relayed to Earth, where analysis would be performed.

This method is generally applicable for screening high-resolution images of any geological or

geomorphological feature. It could greatly increase the success rate of costly sampling procedures by

preselecting suitable areas with a minimum of expense and without additional and costly onboard

equipment. It is expected that it could be developed within 3 or 4 years.

Because the experiment would use available video images, no technical problems are expected.

The computer programs to be developed would be novel, but unlikely to present prohibitive

problems.


During a mission to the surface of Mars, select, high-resolution (~ 1 cm) images taken on the

Martian surface would be transmitted to Earth for computer analysis. No real-time procedures would

be required. After an initial computer screening, visual interpretations would be correlated with other

data from the site. Pre-selected images would be visually analyzed at higher magnification, and

sequential images would also be used for analysis with stereoscopic techniques. Variegated patterns

that could have a biogenic origin would be noted. The interpretations made of the images would not

lead to definitive conclusions about biogenicity. However, analysis could aid in the selection of

samples to be returned to Earth.

23

_ilBl.,,_,,,._..pfl, td _ tltJ_ PRL=CEDING PAGE BLANK NOT FILMED


This experiment is designed to take advantage of any high-resolution images provided by devices

on a lander, penetrator, egg, balloon snake tail, or rover.


The imaging systems on the Viking landers have already produced material of remarkably high

quality. Imaging systems available today are well suited for the purposes of the proposed experi-

ment, and further technological development should not be necessary. The software programs to aid

in the interpretation of the returned images, however, would require development.

24

INFRARED LASER SPECTROMETER FOR IN SITU SENSING OF THE MARTIAN

ATMOSPHERE

C. Webster, T. Owen, and D. Hunten

Objectives

The objective of this experiment is to determine the abundances and possible variability (in space

and time) of minor gases and vapors (e.g., O2, O3, H20) in the Martian atmosphere; to establish iso-

tope ratios of major elements (O, N, C, S) with high precision; and to look for nonequilibrium gases

(e.g., CH4, SO2, and H2S), which may be indicators of biological or geological activity.

This experiment would complement any analyses of volatiles and organics in soils made by other

instruments. The isotopic information gathered would provide the basis for assessing long-term

atmospheric evolution and the history of water and other volatiles on Mars. The discovery of any

nonequilibrium gases or active geothermal areas would be of great importance to the science of

exobiology.


A high-spectral-resolution laser-diode spectrometer with folded-path optics is the recommended

instrument to fulfill the objective of this experiment. The instrument would have a simple, fixed

optical configuration and would be rugged and compact, with a mass of approximately 5 to 10 kg.

Power and data requirements would also be low.


If this instrument were operated during descent, it could acquire spectral measurements over the

depth of the atmosphere. It would, however, be especially interesting to conduct this experiment

from a rover. This would allow a search for local volatile sources and transient volatile releases,

should they occur with concentrations large enough to be detected by the laser-diode spectrometer;

the spectrometer would search for signs of volatiles or biogenic trace gases. Stable deployment of

this instrument on the surface could also be useful, providing measurements over time of diurnal

variations in the local atmosphere.


This experiment could be conducted from a descending probe, a balloon, a rover, or any other

suitable surface platform.

25


This instrument has already undergone a great deal of development and is being used in a num-

ber of applications, including tropospheric and stratospheric studies from balloons and aircraft, and

ground-based industrial diagnostics and environmental monitoring. Currently there is ongoing defi-

nition and development of this laser spectrometer for use on the Titan probe of the Cassini mission.

26

THE DETECTION OF ANAEROBIC CHEMOAUTOTROPHS ON MARS

C. McKay

Objectives

The objective of this experiment is to search for anaerobic chemoautotrophs on Mars. Life may

have survived on Mars in restricted or specialized niches; one possible niche is a hydrothermal vent.

There has been no definite determination of recent volcanic activity on Mars, but the possibility can-

not be excluded. Thus, it is possible that an underground geothermal vent in contact with permafrost

provides the conditions necessary to sustain life. Liquid water would be provided by the melting of

permafrost. Reducing gas (such as H2S, H2, etc.) from the geothermal vent in the presence of Mar-

tian atmospheric CO2 could provide an energy source for Martian chemoautotrophs.

Presumably, missions earlier than the Soviet Mars 94/96 mission, such as Mars Observer, would

be involved in the search for sites of recent hydrothermal activity. Such sites could be recognized not

only from thermal signatures but also from the presence of minerals associated with hydrothermal

alteration. Thus, potential sites for an active biology experiment could be searched for by such

orbital instruments as thermal spectrometers, atmospheric water vapor detectors, Visual and Infrared

Mapping Spectrometers (VIMS), or other spectral instruments aimed at identifying trace amounts of

biogenic gases, such as CH4 or N20, in the atmosphere.

The search for extant life on Mars remains a compelling science driver for exploration of the

planet. If prior orbital survey missions determine that there are present (or recent) sites of volcanic or

hydrothermal activity on Mars, this will motivate the serious search for organisms capable of utiliz-

ing such sites--anaerobic chemoautotrophs. Instrumentation to conduct the search for these organ-

isms could be based on the Viking Gas Exchange (GEx) instrument, minimizing technology devel-

opment. Furthermore, such an instrument could share features with one designed to investigate the

mineralogy and possible organic material at sites chosen for the search for evidence of extinct life.

Although hydrothermal sites are emphasized in this proposal, the instrument concept is applicable to

other sites whose characteristics are consistent with extant life.

Proposed Instrument

The proposed instrument for the detection of a possible Martian biota would consist of a reaction

chamber into which Martian soil samples could be introduced along with a number of gases or liq-

uids. The headspace gas in the chamber could be monitored or sampled to determine the consump-

tion of reagent gases or the release of product gases. The chamber would have the ability to be

heated to pyrolytic temperatures, decomposing any organic material within. The evolved gases

would be analyzed by gas chromatography.

27

Experimental Protocol.

The instrument concept described here is similar to the Viking GEx. Martian soil would be

injected into an incubation chamber, where the temperature could be regulated. Various gases (H20,

H2, H2S, etc.) could then be introduced into the chamber either alone or in combinations. If the

sample is from a geothermal environment, the temperature of the chamber would be set to match the

temperature of the environment from which the sample was obtained. As the sample incubates, the

headspace gas would be analyzed to determine any changes caused by reactions within the chamber.

This would be accomplished by withdrawing a sample of gas and analyzing it with a gas chromato-

graph (GC). The indication of microbial activity is the consumption of a feedstock gas (such as H2)

and the release of a product gas (such as CH4, released from 4H2 + CO2 --_ CH4 + 2H20). The

chamber would then be heated to pyrolytic temperatures to decompose any organic material

produced. Control studies would be needed to lessen the chance of confusion with mineral-mediatedreactions.


This instrument could be deployed on a penetrator or a rover. A major technical consideration

would be sample handling and acquisition; sampling technologies for eggs and penetrators are as yet

undefined.


The proposed instrument is based on the Viking GEx instrument. The major technology compo-

nents, such as liquid water reservoirs, valves, actuators, etc., are already available. GC technology is

also well developed. The Cometary Ice and Dust Experiment (CIDEX) instrument (gas and particle

GC analysis system), which is under construction for the Comet Rendezvous/Asteroid Flyby

(CRAb-') mission, contains many of the subunits necessary for the instrument proposed here.

28

SUMMARY AND RECOMMENDATIONS

This report describes a wide range of instrument concepts for Mars missions; they address many

of the major exobiological issues identified to date. Specifically, the instrument concepts relate to the

search for (1) evidence for extinct life, (2) evidence for extant life, (3) geological evidence for pale-

oenvironmental conditions conducive to the early development of biota or prebiotic chemistry, and

(4) evidence for contemporaneous surface processes. The experiments proposed also offer a variety

of environments in which these lines of evidence might be sought. Some experiments are appropriate

for regolithic sites occupied or formerly occupied by biota, some are appropriate for any regolithic

site on Mars, and one is appropriate for atmospheric investigation.

There is equal variety in the technological methods proposed for conducting experiments; the

techniques include gas chromatography, mass spectrometry, laser spectrometry, thermal analysis,

neutron scattering, electrode sensing, specific-element detection, and pattern recognition. This

variety potentially allows flexibility in accommodating exobiological experiments on highly

constrained missions, such as those with penetrators or eggs.

Specific consideration was given to the matching of instrument concepts with candidate mission

types. Some instruments (e.g., neutron spectrometer) were considered sufficiently light and compact

that they could be accommodated within the snake tail of a balloon. Others (e.g., mass spectrometer)

were considered most appropriate for landers or rovers, where mass and volume constraints are an

order of magnitude less restrictive. For certain instrument concepts (e.g., differential scanning

calorimeter/evolved gas analyzer), it was possible to define an evolving series of instrument configu-

rations that can grow in sophistication in accordance with a growth in payload. For example, thermal

analysis/processing of soil could be conducted by simple pyrolysis for very restricted payloads, but

differential-scanning calorimetry could be used when payloads are least restricted. Similarly, some

instruments (e.g., specific electrodes) were Viewed as modular concepts, so that a central or core

analyzer could be interfaced with a series of augmenting units as payload constraints permitted.

Specific consideration was also given to technology heritage. At the outset of the workshop, a

brief "catalog" of technologies was made available that summarized the types of instruments and

instrument subsystems that could be adapted from Viking, Pioneer, and other engineering designs.

Workshop participants were requested to consider instrument concepts that made maximum use of

this available technology. It transpired that in some cases the apparatus could directly utilize hard-

ware that has Viking or Pioneer heritage; in other cases, the apparatus would only require reconfigu-

ration of flight-proven hardware. (Some experiments do not even require flight hardware, but simply

utilize the output from such generic equipment as cameras.) Those experiments proposing the use of

"new" flight instruments would not require major technology development because the equipment

has already been tested in other, Earth-bound applications.

The workshop provided a forum for the discussion of both scientific and technological aspects of

Mars exobiology. A consensus emerged regarding basic exobiological objectives in the exploration

of Mars (e.g., searching for both extant and extinct life, and understanding the basic chemistry of the

Martian environment), although there was less of a consensus regarding the relative merits of differ-

ent types of scientific information and the way in which the information should be sought (e.g., the

29

mostdefinitivephenomenafor indicatingpastlife on Mars). Because the focus of the workshop was

instrumentation, there was insufficient time to fully debate the exobiology science. A future work-

shop specifically addressing the science goals may be fruitful. The agenda of such a workshop might

include consideration of the phasing of data acquisition, given the potential for a progressive

increase in the sophistication of missions.

In light of the workshop, it is possible to recommend some activities that would help promote

and consolidate near-term Soviet/U.S. cooperation in the area of exobiological exploration. The

following are recommended:

1. A workshop focusing on the science strategy, as suggested above.

2. The selection, by existing joint Soviet/U.S. working groups, of potential exobiology explo-

ration sites on Mars, and an agreement on the next stage of instrument development.

3. An immediate start of funding for the development of instrument concepts. This development

would not include flight hardware, but would include concept feasibility studies, the testing and

refining of analytical techniques, the calibration of instruments through the acquisition and testing of

field analog samples, and the fabrication of breadboard prototype instruments.

4. A joint Soviet/U.S. workshop on exobiology and the Soviet Mars 94/96 mission. The agenda

might include a briefing by the Soviets on the payload constraints likely to be imposed on near-term

missions, current Soviet thinking on mission goals, and identification of candidate experiments for

detailed development.

30

WORKSHOP PARTICIPANTS

Dale Andersen

Lockheed

600 Maryland SW, Suite 600

Washington, DC 20024

(202) 863-5258

Dr. Don Canfield

MS 239-4


Moffett Field, CA 94035-1000

(415) 604-5784

Glenn C. Carle

MS 239-12



(415) 604-5765

Dr. Michael Carr

U.S. Geological SurveyMS 946

345 Middlefield Rd.

Menlo Park, CA 94025

(415) 329-5174

Dr. Sherwood ChangMS 239-4



(415) 604-5733

Dr. Ben Clark

Martin Marietta Corp.

Department 0560P.O. Box 179

Denver, CO 80201

(303) 971-9007

Dr. Dale Cruikshank

MS 245-6



(415) 604-4244

Dr. Robert DayTRW R1-1104

I Space ParkRedondo Beach, CA 90278

(213) 812-0369

Dr. David Des Marais

MS 239-4



(415) 604-6110

Dr. Donald DeVincenzi, ChairmanMS 245-1



(415) 604-5251

Dr. Imre Friedmann

Dept. of Biological Sciences

Florida State UniversityTallahassee, FL 32306

(904) 644-5438

Dr. W. R. Gardner

College of Natural Resources

University of CaliforniaI01 Giannini Hall

Berkeley, CA 94720

(415) 642-7174

Dr. Harold P. Klein

Biology Department

Santa Clara University

Santa Clara, CA 95053

(408) 554-4496

Dr. D. Lowe

Department of Geology

Stanford UniversityStanford, CA 94305

(415) 725-3040

Dr. Rocco Mancinelli

MS 239-12



(415) 604-6165

Dr. John Marshall, Co-chairmanMS 239-12



(415) 604-3668

Dr. Chris McKayMS 245-3



(415) 604-6864

Dr. David Morrison

MS 245-1



(415) 604-5028

Professor Alfred Nier

School of Physics and Astronomy

University of Minnesota116 Church Street

Minneapolis, MN 55455

(612) 624-6804

Dr. John Oro

Dept. of Biochemical and Biophysi-cal Sciences

University of Houston4800 Calhoun Rd.

Houston, TX 77004

(713) 749-2828

Dr. James Pollack

MS 245-3



(415) 604-5530

Dr. Lynn RothschildMS 239-12



(415) 604-3213

Dr. Dale Rushneck

Chemex International, Inc.

225 Commerce Drive

Fort Collins, CO 80524

(303) 490-1511

Dr. AI Seiff

MS 245-1



(415) 604-5685

31

Deborah Schwartz-KolyerMS 239-12



(415) 604-4204

Dr. Carol Stoker

MS 245-3



(415) 604-6490

Dr. Robert Wharton

Desert Research Institute

P.O. Box 60220

Reno, NV 89506

(702) 852-5012

ADDITIONAL CONTRIBUTORS

Dr. Don Hunten

Dept. of Planetary Science

University of Arizona

Space Science Building

Tucson, AZ 85721

(602) 621-4002

Dr. Toby Owen

Institute for Astronomy

University of Hawaii2680 Woodlawn

Honolulu, HI 96822

(808) 948-8312

Dr. C. Webster

Earth and Space Science DivisionMS 183-301

Jet Propulsion Laboratory4800 Oak Grove Drive

Pasadena, CA 91109

(818) 354-7478

32

ru/LsANalomd/_leOMiJl_l end

_Inla'Wion

1. Report No.

NASA CP-10055

4. Titleand Subtitle

Exobiology on Mars

Report Documentation Page

2.Govemment Accession No.

7. Author(s)

D. L. DeVincenzi, J. R. Marshall, and D. Andersen, Editors

9. Performing Organization Name and Address



12. Sponsoring Agency Name and Address

National Aeronautics and Space Administration

Washington, DC 20546-0001

3. Recipienrs Catalog No.

5. Report Date

December 1990

6. Performing Organization Code

8. Performing Organization Report No.

A-90320

10, Work Unit No.

199-59-12-05

11. Contract or Grant No.

13. Type of Report and Period Covered

Conference Publication

14. Sponsoring Agency Code

15. Supplementary Notes

Point of Contact: D.L. DeVincenzi, Ames Research Center, MS 245-1, Moffett Field, CA 94035-1000

(415) 604-5251 or FTS 464-5251

Proceedings of a meeting held at Ames Research Center on February 27-28, 1989.16. Abstract

This report contains descriptions of several instrument concepts that were generated during a

workshop titled "Exobiology Instrument Concepts for a Soviet Mars 94/96 Mission" held at NASA

Ames Research Center on February 27-28, 1989. The objective of the workshop was to define and

describe instrument concepts for exobiology and related science that would be compatible with the

mission types under discussion for the 1994 and 1996 Soviet Mars missions. Experiments that use

existing technology were emphasized. The concepts discussed could also be used on U.S. missions

that follow Mars Observer.

17. Key Words (Suggested by Author(s))

Exobiology

Mars exploration

Soviet spacecraftMars soil

t8. Distribution Statement

Unclassified-Unlimited

Subject Category - 55

19. Security Classif. (of this report)

Unclassified

20. Security Classif. (of this page)

Unclassified

21. No. of Pages

4222. Price

A03

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